Many modern refrigerators include an evaporator which normally operates at below freezing temperatures, at which a layer of frost builds up on the surface of the evaporator. In order to quickly defrost the evaporator, a radiant heater is positioned below the evaporator so that the evaporator is warmed by both radiant and convection heating. One suitable type of radiant heater comprises a coil of heater wire encased in a heat resistant and electrically insulated tube of quartz or similar material. Such heaters operate at temperatures above the boiling point of water and quickly warm the surface of the evaporator to defrost temperatures. When the frost melts, the defrost water drops down. If it is allowed to impinge on the heater structure it will produce undesirable noises during defrost operations. It is well known to provide some type of shield to prevent the water from impinging directly upon the heater. One such shield structure is shown in U.S. Pat. No. 3,436,931--Robert B. Gelbard, assigned to General Electric Company, assignee of the present invention; which patent is incorporated herein by reference. It is normal to provide a single evaporator for both the freezer and the fresh food compartment and to place the evaporator in an evaporator compartment positioned behind the freezer compartment. Such arrangements are crowded and it is difficult to both shield the heater from direct impingement by defrost water and to effectively and uniformly defrost the evaporator.
An object of the present invention is to provide an improved evaporator and defrost heater combination which shields the heater from direct impingement by defrost water while providing enhanced evaporator defrosting action.
Another object of the invention is to provide a heater and housing arrangement which provides uniform transfer of heat from the heater to the evaporator while shielding the heater from direct impingement by defrost water.
Yet another object is to provide such an arrangement in which the housing compensates for the uneven heat distribution from the heater.
Further objects and advantages of the invention will be apparent from the following description and features of novelty which characterize the invention will be pointed out in the claims attached to and forming part of this specification.